The clues to the origin of life itself on Earth could reside, precisely, outside it; although, yes, on one of the planets most similar to her ever studied. It is about Mars and the discovery of a large and ancient hydrothermal reservoir on the red planet. Conditions that have existed for billions of years on Earth and which many scientists call the ‘primeval soup’, since it is assumed that the first life forms flourished here.
A planet similar to ours, yes, but dead , given that the geological processes that make life possible probably stopped on Mars a long time ago. Still, it is similar to Earth in size and gravity, and could also have supported primitive life, which would have arisen in the same way as on Earth: in these hydrothermal reservoirs.
We explain it.
A recent international study has examined observations from NASA’s MRO (Mars Reconnaissance Orbiter) reconnaissance instrument, which has studied large ocean basins on the planet, such as the Eridania basin.
After careful analysis, the authors interpret the data as evidence that these deposits were formed by boiling water from remote volcanic activity in the planet’s crust , and that it was located at the bottom of this great sea millions of years ago.
Under these conditions, theoretically, the chemical broth of life becomes possible : elements and chemical reactions that made the first microorganisms thrive. It is estimated that, at least, this was the case on Earth.
This diagram illustrates a possible origin of deposits in the Eridania basin of southern Mars as a result of hydrothermal activity on the seafloor more than 3 billion years ago. / NASA
“This ancient Martian deposit can tell us a lot about the kind of environment that must have reigned on Earth in the early days, immediately before life formed ,” in the words of NASA Johnson Space Center researcher Paul Niles. “The volcanic activity combined with the standing water provided conditions similar to those that occurred on Earth when early life was evolving here,” he explains.
But today Mars no longer has stagnant water or volcanic activity. This phenomenon occurred, according to the predictions of scientists, about three thousand seven hundred million years ago. This is the age attributed to their hydrothermal conditions, the same ones that once existed on Earth, and which are the ones that made possible the environment in which life began on our planet.
Precisely the same age in which, scientists estimate, life formed on Earth, in these hydrothermal conditions: under the sea, in submarine volcanic vents at high temperatures and, surprisingly, in the most complete darkness , without sunlight .
In fact, the Earth still has these conditions. In them, many life forms succeed without solar energy: they extract chemical energy from rocks.
A clue to find life on other planets
And if this happens on our planet, why not in other corners of the solar system? The discovery of this ancient haven of hot springs on Mars raises the possibility of life within icy moons of the Solar System, such as Europa on Jupiter and Enceladus on Saturn, where it is possible that this hydrothermal activity also occurs.
And how, if they are so far from the Sun? Although these bodies are outside the so-called ‘habitable zone’, it is also true that they could extract heat from their own nucleus , still hot, or agitated by the intense gravity of the gas giants they orbit. And, as on Earth, extracting energy from rocks, in the dark.
NASA’s MRO observations have also provided data to identify minerals in the Eridania basin , which is in a region that contains some of the oldest remains of the red planet’s crust. The mixture of minerals identified includes serpentine, talc, and carbonate. In fact, it was the shape and texture of the thick bedrock layers that led to the identification of possible hydrothermal deposits on the seafloor.
“This place tells us a pretty compelling story: a deep, long-lasting sea and a deep-sea hydrothermal environment,” explains Niles. “It evokes the hydrothermal environments of the high seas on Earth; and in places on other worlds similar to these we could find life .”
Of course, the kind of life that does not need a pleasant atmosphere or warm surface, or even light; but only rocks, heat and water.
“The Eridania seafloor deposits are not only of interest for exploring Mars, but are a glimpse of early Earth,” say the researchers.
The window to our first ancestors
The window to the origins of our own existence, to our most remote ancestors, could reside in our closest neighbor, Mars.
Could this indicate that, in some way, life was born earlier on Mars than on Earth, and then moved to our planet?
It is another question that, at the moment, does not yet have an easy answer.
References:
Joseph R. Michalski, Eldar Z. Noe Dobrea, Paul B. Niles & Javier Cuadros. ‘Ancient hydrothermal seafloor deposits in Eridania basin on Mars’. Nature Communications 8, Article number: 15978 (2017). Doi: 10.1038 / ncomms15978
Image credit: NASA
